Tax calculators can be a useful tools for tax planning and cash flow forecasting. A self assessment tax return calculator can help you assess how much income tax you need to pay if you're a sole trader and pay tax via self assessment. They can also help you estimate future tax bills, so that you can arrange financing if needed. You can also use tax calculators to check payments for past tax years
There are different calculators to help you with different tax liabilities. An income tax calculator, for example, can help you estimate future tax bills, while a company car tax calculator can help you compare the tax impact of different company car choices.
Remember: any calculator will have limitations and cannot take into account your detailed personal circumstances. If you want a detailed picture of your self assessment tax liabilities, you should take advice from your accountant, particularly if you are self-employed.
Here is a round-up of the best tax calculators available online, including those from official bodies such as HMRC and the Valuation Office.
Self assessment tax return calculators
- estimate your self assessment tax bill if you're self employed - you'll need tan estimate of your weekly or monthly profits, after taking into account any allowable expenses that you can deduct from your turnover
- this income tax calculator for employees can handle details like pension contributions and offers both 'simple' and 'advanced' version
- use simplified tax calculator for the self-employed
If you use HMRC's Self Assessment online service, tax calculations will be handled automatically (so you will not need a calculator.) You can 'view your calculation' once you have completed the details in the return, but before you submit the return. Once you have submitted the return, your final tax calculation will be available in your online personal tax account within 72 hours.
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For self-employed individuals, sole traders, or those with non-PAYE income, GoSimpleTax provides direct Self Assessment filing with HMRC, offering helpful hints and savings tips throughout the process. Let GoSimpleTax handle all calculations.
Capital gains tax calculators
You may need to pay capital gains tax (CGT) if you sold assets and made a gain greater than the annual exempt allowance (£3,000 in 2024/25). Different allowances applied in previous tax years. You can use these tax calculators and tools to work out how much taxable gain you have, and what CGT is payable:
- CGT calculator for shares on the GOV.UK website
- CGT calculator for property on the GOV.UK website
- this CGT calculator can help you estimate your potential CGT liability on disposals of property or shares
- download the HMRC capital gains tax for Shares toolkit (PDF)
Sole trader v Ltd company tax calculator
- this sole trader versus limited company tax calculator will estimate the difference in take home pay depending on the form your business takes simply by inserting an estimate of your annual profit
Income tax and National Insurance calculators
- estimate your income tax for the current tax year with this HMRC calculator
- estimate your income tax for a previous tax year with this HMRC calculator
- work out income tax and employer and employee NICs with this income tax calculator
- get a more detailed income tax calculation, including pension contributions, with this income tax calculator
- use this net salary calculator on the MoneySavingExpert website to work out your take-home pay after all deductions
The HMRC self-assessment ready reckoner provides an estimte of income tax and Class 4 NICs. You can get a clearer idea of your tax liabilities by completing your tax return online or by taking advice from your accountant.
If you own a personal services company, you can assess the extra tax and NICs you may have to pay on dividend payments using the IR35 - deemed payment calculator and guidance.
The rules on IR35 have changed, so do your research. If in doubt, always take advice from a qualified accountant.
Payroll calculators
HMRC provides a range of calculators you can use when managing payroll deductions:
- download HMRC's basic PAYE tools that enable you to perform most payroll tasks
- work out an employee's income tax with this PAYE calculator
- work out an employee's with this National Insurance contributions
- use this directors' annual NICs calculator to work out a director's NICs for the current tax year
- calculate your employee's Statutory Sick Pay (SSP)
- calculate an employee's Statutory Maternity, Adoption or Paternity Pay
Company car tax calculators
- calculate the tax on employees' company cars with the HMRC company car tax calculator
- work out the company car tax and car fuel benefit for employees (you will need to complete details such as emissions and list price)
- find the HMRC approved mileage rates that can be used to calculate allowable motoring expenses
- this company car tax calculator will work out the benefit in kind tax on company cars
- this simpler company car tax calculator can be used to check current and historic benefit in kind tax details.
Corporation tax calculators
Corporation tax calculations are generally complex, relying on detailed information about income and expenses. Various online tax calculators can help with simple guidance and estimates:
- use this corporation tax calculator to assess liability based on profits
- enter your Gross Profit and select the tax year to calculate your corporation tax
- calculate marginal relief for corporation tax with this HMRC calculator
For a fuller assessment of your tax liability, you should take advice.
VAT calculators
- a VAT payment deadline calculator from HMRC
- A VAT registration estimator to work out what registering for VAT might mean for your business
- work out how much VAT you need to charge on standard-rated supplies
- work out VAT fuel scale charges on business cars with private use
Property tax calculators
- estimate your business rates bill using the guidance on the GOV.UK
- HMRC stamp duty land tax (SDLT) calculators to work out how much SDLT might be payable on a property purchase.
- Download the HMRC capital gains tax for land and buildings toolkit (PDF) which aims to support tax agents and advisers with guidance on fixing common errors.
